Your numbers are still wrong, but that's not really the point. Even if we conceded everything you arguing: that we should only look at the people getting a tax break and ignored the "few" (millions of) working class people getting no relief or a tax hike; even if we assume that those getting a break are getting around 3%; even if we ignore that that the cuts are less meaningful over time due to other provisions in the bill; even if we assume Congress will eventually make the individual cuts permanent making the 8-10 year numbers less damning - all of that could be true and the bill would still be AWFUL.
The "most people get more in their paycheck so this should be getting more support" argument completely ignores the fact that we don't have infinite money. This costs $2.2 trillion dollars (if the cuts are made permanent), which everyone should agree is not sustainable, and no analysis, even from the right leaning think tanks, has shown that the cuts will come close to paying for themselves. That money has to come from somewhere, and it will, whether it starts this year with mandated big cuts to Medicare and other programs via Paygo, Medicaid/SS/entitlement programs cuts to be introduces soon, some silly clawback provision that raises taxes when fairy tale revenue targets aren't met, or the eventual expiration of the cuts in 2025, or some combination of the above, it will happen. And wherever the money comes from, I'm confident it will disproportionately hurt the lower and middle classes. There are other things that are terrible about the bill (premiums going up 10%, crippling graduate education, etc) any of which could be reasonably considered disqualifying, but it doesn't matter because we can't pay for it.